This invention relates to a portable generator, in particular to its cooling system, which houses an engine and a generator directly connected to and driven by the engine within a casing.
The prior art for the cooling system of portable generators, which house an engine and a generator directly driven by the engine within a casing, is as follows: Cooling fans are installed respectively on the crankshaft of an engine and on the revolving shaft of a generator; ambient air is drawn at some openings in the vicinity of the engine and generator of many ventilation openings drilled in casing end walls respectively facing the side surface opposite to the connecting portion of the engine and the generator, passes through the inside of an engine baffle cover and a generator case, and flows out from the engine baffle cover and the generator case to the periphery in the vicinity of the connecting end of the engine and the generator, to mingle together and again flow out to the outside of the casing from some openings around the air intake openings among a number of ventilation openings in both casing end walls, through the space between the outer surfaces of the baffle cover and generator case, and the inner surface of the generating set casing.
With the cooling system of the prior art, there have been such drawbacks as follows: Since the hot exit air passing around the air intake openings flows opposedly to the cool intake air, drawn from ventilating openings in casing end walls for cooling the engine and generator, there are large flow disturbances, resulting in not only a considerable level of noise, but also insufficient cooling of the engine and generator, because part of the hot exit air mixes with the cool intake air, and the counterflow of the intake air for cooling the engine and the intake air for cooling the generator produces air stagnation in the casing.